The embodiment relates to a light emitting device package and a lighting system.
A light emitting device (LED) includes a p-n junction diode having a characteristic of converting electric energy into light energy. The p-n junction diode can be formed by combining group III-V elements of the periodic table. The LED can represent various colors by adjusting the compositional ratio of compound semiconductors.
When forward voltage is applied to the LED, electrons of an n layer are combined with holes of a p layer, so that energy corresponding to an energy gap between a conduction band and a valance band may be generated. This energy is realized as heat or light, and the LED emits the energy in the form of light.
In order to improve the quantity of light of the LED, the efficiency of an LED chip must be increased, and the damage of a package surrounding a chip must be reduced.
Accordingly, the lateral surface and the bottom surface of the package may include a reflective layer (mirror) including Ag-based materials having high reflectance.
However, according to the related art, a flat mirror reflects light only in an original direction, and does not diffuse or diffract light. Accordingly, the flat mirror cannot be used to extract light at the boundary surface between an encapsulant and the air.
In addition, according to the related art, in order to maintain the reflectance of the reflective layer, a capping layer must be coated. However, the reflectance of the capping layer is exponentially inverse-proportion to the thickness of the capping layer.